Tony Stewart to miss start of NASCAR season with back injury

Tony Stewart's last season before retiring will be truncated, as the three-time NASCAR Cup Series champion is out for an indefinite amount of time after suffering a burst fracture of the L1 vertebrate in an all-terrain vehicle accident, Stewart-Haas Racing announced Thursday.

Stewart injured himself while driving a sand buggy in the Southern California desert last Sunday. He was immediately taken to a San Diego area hospital then transported to a Charlotte, N.C., medical facility Tuesday night where he underwent back surgery Wednesday. He is expected to make a "full recovery."

The number of races the 44-year-old will miss is unspecified but he is assured of sitting out the season-opening Daytona 500, the sport's marquee event which Stewart has failed to win in 17 previous attempts. He had already announced 2016 will be his last as a full-time NASCAR driver,

Stewart was with a group who attended the Barrett-Jackson auction in Scottsdale, Ariz., on Saturday before going dune buggying the following day. NASCAR driver Greg Biffle was among those with Stewart, though he did not witness the incident firsthand.

During an interview on SiriusXM Radio on Wednesday night, Biffle said he was told Stewart was walking immediately after the incident and had movement of his extremities but was in obvious and great pain.

"We were all kind of riding as a group," Biffle said. "Phone service was terrible ... we started hearing bits and pieces that he hurt his back. That's all we knew. We didn't know anything else about it and really don't. I haven't talked to (Stewart) or found out any more about exactly what happened or how severe an injury it is.

"I do know that the people that helped him, I don't know if he got out of the car on his own, but he was like walking and moving all his extremities and all that, but he was in a lot of pain. I think everybody has had some kind of back injury at one time or another and knows how tough it is to get around."

Stewart's back injury marks the third time over the past 30 months that he will have been sidelined due to outside factors not directly related to NASCAR competition.

In August 2013, Stewart badly broke his right leg in a dirt sprint-car race that caused him to miss the final one-third of the NASCAR season (15 races).

Twelve months later Stewart clipped and killed Kevin Ward Jr. during a sprint-car race at Canandaigua (N.Y.) Motorsports Park. Stewart and Ward had just been involved in an accident and an upset Ward was on the track seeking to confront Stewart when he was struck.

Stewart said he never saw the 20-year-old and a grand jury later absolved him of any criminal wrongdoing. Stewart sat out three NASCAR races dealing with grief that caused him to become a recluse, struggling to function with day-to-day activities.

Nearly one year to the day of the accident, Ward's parents filed a wrongful death lawsuit against Stewart. The case remains open.

SHR, which Stewart co-owns with Gene Haas, has not named a replacement to drive Stewart's No. 14 car. The team also fields cars for Kevin Harvick, Kurt Busch and Danica Patrick. The Daytona 500 is Feb. 21 at Daytona International Speedway.

Stewart can still gain eligibility for NASCAR's Chase for the Sprint Cup championship playoff, provided the sanctioning body grants him a medical waiver. If Stewart receives an exemption, he would need to win one regular season race and rank 30th or better in points.

Kyle Busch was allowed such a waiver last year after he broke his right leg and left foot in a crash during the Xfinity Series race at Daytona International Speedway, which was held one day prior to the Daytona 500. After missing 11 races rehabilitating, Busch returned to win four regular season races to qualify for the Chase. He capped his improbable comeback by becoming the first driver in NASCAR's modern era (1972-to-present) to miss a race but still capture the championship.